can i change time format in access log?

[appchemist]

I have one more question about access log.
there is a +0900 in 21/Mar/2013:18:47:32 +0900, 2013-03-26T10:27:40+09:00

what does +0900 mean?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,237780,237787#msg-237787